The work in this grant deals with the development of obesity in experimental animals. The two models of obesity which have been selected for study are the fatty rat (Zucker rat) and the obese (ob/ob) mouse both of which are autosomal Mendelian traits. The other type of obesity is that due to hypothalamic injury. Recent data from our laboratory has shown that the genetically transmitted forms of obesity are related to changes in endocrine function whereas the hypothalamic obese animal is due to alterations in autonomic nervous system function. We plan to continue evaluation of these types of changes in these groups of animals.